1. Field of the Invention
The present invention relates to a structure for a promotional coupon attachable to the surface of containers used in refrigerated and other moisture-laden environments. More specifically, the invention relates to a wet-strength coupon structure consisting of a base ply and a top ply with a fugitive adhesive therebetween to permit removal and redemption of the top ply.
2. Description of the Related Art
Recently, packages and containers have utilized pressure-sensitive peel-off and/removable coupons as secondary elements of the container. See, e.g., U.S. Pat. No. 4,994,089 to Schwartz; U.S. Pat. No. 4,767,654 to Riggsbee; U.S. Pat. No. 4,863,772 to Cross; U.S. Pat. No. 4,345,393 to Price et al.; U.S. Pat. No. 4,281,762 to Hattimer; and U.S. Pat. No. 4,479,838 to Dunsirn et al. The inventions disclosed in all of the above patents address promotional needs of manufacturers with no regard to the problems faced in a moisture-laden environment. However, in a condition where refrigeration and continual removal from refrigeration occurs, condensation may form on a container as a condition of temperature and humidity. Degradation of normal untreated paper occurs rapidly as moisture penetrates the porous paper surface.
More than 20 years ago, improvements in paper making resulted in water-resistant products. Papers that were high in water repellency, and improved wet-strength characteristics became commercially available. U.S. Pat. No. 3,589,978 to Kamal; U.S. Pat. No. 3,640,840 to Zieman et al.; U.S. Pat. No. 3,657,066 to Chene; U.S. Pat. No. 3,679,544 to Ashikaga et al; and U.S. Pat. No. 3,740,253 to Hattori relate to the manufacture and structure of highly water-resistant papers. Such wet-strength papers typically utilize self-cross-linking water soluble reaction products or resin precursors such as melamine formaldehyde to improve the bonding between paper fibers and thus their wet-state condition.
Although removable coupons and wet-strength labels are both available, no coupon structure has been devised to date which combines the features of removability and wet-strength. Yet, there is a long-felt need for such a structure, particularly for refrigerated products.